Although it is possible to take control of a minion, it is not possible to take control of effects on that minion. For example, Death Nova will damage the enemies of whoever cast it and not the present controller of the minion. Similarly, Dwayna's Sorrow will heal the party of the caster. The exception to this is Jagged Bones, which will create a minion under the control of whoever controls the minion when it dies.

Bug. When casting Verata's Gaze on a masterless minion that was in a well, the effects of that well will persist even after the minion leaves, until the well expires.